Vinylidene fluoride resin is excellent in chemical resistance, weatherability, wear resistance, electrical properties, etc. and also has good processability, so that it is used as materials for various purposes. However, as vinylidene fluoride resin is a hydrophobic resin having a low surface energy, it is accompanied with problems, such as inferior adhesiveness with other parts or materials and adhesion of soils thereto, depending on some use thereof. Accordingly, various means for hydrophilization thereof have been proposed. For example, Patent document 1 listed below has disclosed a means for hydrophilization according to chemical treatment, but it is not only costly and troublesome but also liable to impair the characteristic properties of vinylidene fluoride resin. Patent document 2 below discloses a means of copolymerization with a hydrophilic monomer but the species and amount of such copolymerizable monomers are limited. Further, Patent document 3 below discloses a mixture with another hydrophilic resin, but it is difficult to obtain a uniform mixture. From a viewpoint of improving the homogeneousness of a mixture, there has been proposed a composition obtained by adding another monomer to a polymerization vessel after suspension polymerization of vinylidene fluoride and polymerizing the added monomer by utilizing a polymerization initiator remaining in vinylidene fluoride polymer particles (Patent document 4 below), but this is for the purpose of controlling the crystallinity of vinylidene fluoride resin, and no attention has been paid to provision and persistency of hydrophilicity.    Patent document 1: JP-A 2004-230280    Patent document 2: JP-B 3121943    Patent document 3: JP-B 3200095    Patent document 4: JP-B 52-38586